This invention relates generally to a window structure, and more particularly to a sliding window structure that includes two casements (sashes) balanced by suspended counterweights, and even more particularly to sliding window structures commonly known as “double hung” windows, as might be found in Colonial style homes, for example.
Typically, in modem architecture, side-hinged windows, bottom-hung sashes, side-hinged and bottom hung windows, swivel frame windows, swinging windows and sash windows are used. A disadvantage of traditional side-hinged and bottom-hung windows is that in an open state, the side-hinged windows protrude deeply into the space of the room, whereas bottom-hung casements provide only limited possibility for allowing air to pass, and do not allow for a direct opening with the outside environment. A combination of these two types, side-hinged and bottom-hung windows, solves this problem relatively well, but producing operable hinges of appropriate load capacity imposes serious problems and significant costs.
In the case of swivel-swinging windows, the axis of rotation is aesthetically disturbing, and it is cumbersome to fix and to operate such windows. In one relatively simple solution, i.e., a double hung window arrangement, casements, or sashes, are movable separately in two glideways offset from and parallel to each other. This allows either the window on one side to be slid beside the other one, or the opposite way, or allows each of the casements (sashes) to be slid in the direction of the other. However, in all of these cases, double hung windows included, the free surface that may be provided is, at most, half of the area of the whole window opening.
Moreover, this solution is also aesthetically disadvantageous, since in the closed state, the two casements (sashes) are not in the same plane. Though sash-windows exist in which the casements (sashes) are in the same plane in their closed state, the free opening in this example is also only half of the whole window opening.
Experiments have also been carried out with casements transformable to opening casements after opening them, and pushing them to their place. The advantage of this solution is that the whole window opening can be made free, but its disadvantage is that the natural advantage of sash-windows, i.e., that a window opening of arbitrary size can be produced, is hindered by this solution.
Further, there is a significant demand for new window structures such as double hung windows in newly-constructed houses or in remodeled houses of the Colonial style, for example, which allow fully opening the casements to allow air flow into the house.
What is needed then is a sliding window structure which is producible with an arbitrary window opening size. What is further needed is a sliding window structure in which it is possible for the whole window opening to be opened to the external environment. What is still further needed is a sliding window structure in which the closed state can be produced by casements or sashes in one plane, and which is suitable as a substitute for conventional double hung windows in new construction homes or remodeled.